The main aim of an aerator is to supply new air into the water contained in an aquarium or pond with a new amount of oxygen. Air put into the aquarium rises, so moving water and thus creating a more efficient vertical circulation and gas exchange on the water surface. It is also to be noted the pleasant visual effect which the flow of air bubbles produces by rising up to the water surface.
A first kind of aerators of the prior art are made up of an alternative pump with a membrane, that is a casing wherein there is a membrane alternatively moved by an electromagnet fed by alternating current. On the casing, there is an intake to be connected to a sucking duct in order to suck air and an outlet to be connected to a delivery duct where air under pressure comes out. The alternative movement of the membrane allows for the air to be sucked from the intake and to send it to the delivery duct. The aerator and the sucking duct are positioned outside the aquarium and only the end portion of the delivery duct is immersed inside the aquarium where, at its end, a porous stone is mounted which allows for the air to spread out, so forming many bubbles which rise towards the water surface.
These aerators of the prior art have many drawbacks. In fact, due to the principle of functioning which is of an alternative kind, vibrations originate and they stress the aerator, so reducing its life time. Moreover, vibrations cause noises and, more precisely, a buzzing which can be very troublesome. The membrane of the aerator continuously vibrates and it is always stressed, therefore it breaks often. Furthermore, air which comes out from the delivery duct through the porous stone, continuously leaves substances into the micro-porosity of the stone which, in a short time and easily, block the delivery duct. Unfortunately, also the valves for the operating of the aerator are liable to damages and they easily fail, thus stopping the functioning of the aerator.
This kind of aerator is complicated in construction since it is made by many components, some of them complex and continuously stressed. It is to be noted that a similar aerator necessitates a long time for construction and high costs. In addition its reliability is very low since it often breaks or malfunctions.
There is a second kind of aerator which use the so-called “Venturi effect”, that is, devices which pump water inside a duct wherein there is a narrowing section connected to a duct for the intake of water. Near the narrowing section, due to the “Venturi effect”, the lower pressure is created, air is sucked and mixed with water and then ejected from the aerator. Also this aerator has some drawbacks due to the fact that the created lower pressure is little, the mixing of air with water is noisy and the dimension of air bubbles are, on the average, very big.
Finally, there exist pumps for aquariums comprising a centrifugal impeller, operated by an electric motor, having a duct for sucking water and a delivery duct. At the sucking duct a passage is made for the intake of air so that, during the operating of the pump and thanks to the lower pressure created by the pump, air is drawn in, mixed with water, and then ejected through the delivery duct. This device is actually a pump, where the main aim is to draw water from an aquarium in order to filter it, and then to re-introduce the water into the aquarium. The water sucked from the pump creates a flow of bubbles, but this flow is very little, thereby it has only an aesthetical effect: in fact, the device is a pump and not an aerator. In conclusion, although the flow of bubbles is visible, it is absolutely insufficient for aerating and/or oxygenating water contained in an aquarium. Moreover, this device, during the functioning, also produces noises which cause nuisance.
Furthermore, the water and air flow which comes out from the aerator has a random orientation, thereby the aesthetical result of the air bubbles which rises towards the water surface is not sufficient in order to create an agreeable visual effect. This aerator is positioned near the water surface and then, the air bubbles, which are drawn by the movement of water, come out quickly and not in the depth.
The aim of the invention is to make an aerator wherein all the drawbacks cited with reference to the prior art described above, are overcome. In particular, it is required a noiseless aerator, free from vibrations. Moreover, it has to produce a more efficient air flow requiring less power. The air flow created has to form a flow of bubbles which rises upwards, so to create a pleasant visual effect. The aerator has to be simple in construction, with few components and it has to be reliable.